In the Standard Model of particle physics, the massless Goldstone bosons resulting from spontaneous symmetry breaking of the Higgs field became longitudinal components of the W and Z bosons and thus make these vector bosons massive. It is critical to study longitudinal-longitudinal scattering of W and Z bosons at the LHC to validate this electroweak symmetry breaking mechanism and to search for other alternative mechanisms. I will present a few studies that are related to vector boson scattering using data collected by the ATLAS detector. In addition, I will discuss Phase-I and Phase-II upgrade activities of the ATLAS muon spectrometer that my research group has been involved in.